Dental cement and process for manufacturing the same.



UNIrnD STATES PATENT OFFICE,

FRANK LAYTON GRIER AND GARRETT LAYTON GRIER, OF MILFORD, DELAWARE.

, -DENT'AL enMEN'rAND rnoonss son MANUFACTURING THE SAME.

Specification of Letters Patent.

Patented May 26, 1908.

Application filed September 4, 1907. Serial No. 391,313. a

22 county of Sussex and State of Delaware,

have invented an Improved Dental Cement and Process for Manufacturingthe Same, of

' which the following is a specification.

Our invention relates to the manufacture of a translucent cement fordental fillings, and consists in mixing solutions of phoshoric acids ora combination of said acids iiolding in solution certain modifyingsalts,

,With compounds of thorium and titanium capable 0 chemical combinationwith the same. Thorium is a rare mineral, the salts of which have neverbefore been used in makin a dental cement, but are possessed of valuableproperties for this pur ose. The cement thus obtained is extreme y hard,of very dense texture and in addition to a marked translucency combinedwith pearllike luster, is susceptible of a high degree of polish whichis lastmg and more perce tible under the influence of moisture, renering it of particular beauty for the purposes intended.

The material obtained by our process closely resembles the human teethin color, and also in its resistance to chemical change through anyaction of the normal secretions occurring in the oral cavity, and as inprocess of manufacture it may be given any desired shade through fusingwith certain oxids including titanium; uranium, and other metallic oxidspossessed of coloring power when fused with silicious compounds, itarticularly ada ts itself to be used as a i1 ling or plugging or teeth,and when properly inserted by the dentist is indistinguishable in colorand texture from the tooth or teeth in which it is placed.

In the manufacture of dental cements of this character, certainrecipitated silicates have been used incom i ation with a base of silicafused with lime, lumina, etc., but these cements have also been adaptedto mending pearls, porcelain, etc., and show either contraction,expansion, solubility, or a lack of strength in varying degrees, such asto render then use unsatisfactory in long tests for dental purposes, andin addition to these mechanical or physical defects, some cementprepared by our process and ready for convenient use by the dentaloperator, avoids these troubles, as it is prepared and adapted fordental use only. It has, through the peculiar action of the thoriumcompound, strength, luster, and insolubility, and as thoria is notdiscolored by action of contents of the oral cavity including hydrogensulfid, which latter discolors most chemical compounds, it retains colorand tooth-like luster. The thorium com ounds as used in our process givestrengt density ,'a tooth-like appearance, and lasting ualities in thepresence of dilute acids or a alies not obtained by any other compoundof like nature, in addition to which it shows remarkable stability ofform as regards expansion or contraction.

The silicate or thorium used in this process may be prepared byprecipitating a solution of nitrate of thorium or other soluble acidsalt of same, by means of a solution of an alkali silicate such assodium or potassium silicates, carefully washing the preci tate, dryingatmoderate heat and finaly bringing to incipient fusion; this treatmenthSiO,. This product is ground and bolted with a base composed of silica,lime, alumina, and titanic acid, (TiO the latter adding greatly tostrength and non-penetrability of the finished cement. The abovementioned materials are mixed with small amount of Na CO in suchroportions that upon fusion they form a hig ily refractory glass. Thisis treated while still hot to remove any soluble matter, and afterwardground with the thorium silicate as described before. The proportionsused, which may be varied to obtain certain results, are 8 parts of thebase to 2 parts of the thorium compound.

The solid pulverulent body of Lhe cement as thus described, isincorporated with hosphoric acid, or its acid salts in the usua Way ofadmixture and quickl' sets into a lasting coherent mass. Instea -ofusing the phosand aluminum salts.

We claim:

LA pr ocess'for m nufacturing a material especially adapta i for tit eas a translucent dental cement, which consists in combining a thoriumcom ound insoluble in resulting in the production of a silicate OOIIB-'s onding in formula with Th0,sio,, or

phoric acid alone, it may be modified by the addition of otheringredients such as zinc water but ca able of c emical reactions withphosphoric acid, with a fused and finely ground base consisting ofsilica, lime, alumina, and titanic oxid, and with phosphoric acid oracid phosphates in solution, substantially as herein set forth.

2. The process for producing a translucent dental cement, which consistsin preparing from its solutions, a thorium silicate and combining thesame With a base contain ing titanium oXid.

3. A process for producing a translucent dental cement, which consistsin combining a thorium compound with a solution of phosphoric acid, or asolution of phosphoric acid modified by the addition of certain solublesalts of zinc, and aluminum.

4. As a new article of manufacture, a

translucent dental cement or filling composed of a thorium compound in0011111110- tron with a base consisting of silica, lime,

alumina, and titanic oXid, in combination with solutions of phosphoricacid substantially as herein set forth.

5. A new article of manufacture for forming a translucent dental cement,consisting of a composition of matter containing a thorium compoundadapted to have a setting reaction With phosphoric acid.

FRANK LAYTON GREEK. GARRETT LAYTON GRIER. VV' tnesses:

S. EDGAR MAHAN, J. D. Pos'rLER.

